Communication networks are used to transport a variety of signals such as voice, video, data transmission, and the like. Traditional communication networks use copper wires in cables for transporting information and data. However, copper cables have drawbacks because they are large, heavy, and can only transmit a relatively limited amount of data. On the other hand, an optical waveguide is capable of transmitting an extremely large amount of bandwidth compared with a copper conductor. Moreover, an optical waveguide cable is much lighter and smaller compared with a copper cable having the same bandwidth capacity. Consequently, optical waveguide cables replaced most of the copper cables in long-haul communication network links, thereby providing greater bandwidth capacity for long-haul links. However, many of these long-haul links have bandwidth capacity that is not being used. This is due in part to communication networks that use copper cables for distribution and/or drop links on the subscriber side of the central office. In other words, subscribers have a limited amount of available bandwidth due to the constraints of copper cables in the communication network.
As optical waveguides are deployed deeper into communication networks, subscribers will have access to increased bandwidth. Deployment of optical waveguides toward the subscriber is generally called fiber to the location x (FTTx) applications and includes fiber-to-the-curb (FTTC) and fiber-to-the-home (FTTH) applications. There are certain obstacles that make it challenging and/or expensive to route optical waveguides closer to the subscriber. For instance, making a suitable optical connection between optical waveguides is much more complicated than making an electrical connection between copper wires. Additionally, as the communication network pushes toward subscribers, the communication network requires more connections, which compounds the difficulties of providing optical waveguides to the premises of the subscriber. Thus, routing fiber optic cables towards the subscribers requires a quick and easy solution for streamlining the installation process. Also, on the end of the network closest to the subscriber, smaller cables housing fewer optical fibers are typically used. Such cables have their own set of particular location, installation, termination, and connectorization issues generally not found with long haul cables.
For example, fiber optic cables routed toward the premises of the subscriber may be buried in the yard of the subscriber. Consequently, these buried fiber optic cables are preferably located and marked to prevent damage to the same before the subscriber or others dig. Generally speaking, the craft prefers dielectric cables since they do not have to be grounded and the like. However, dielectric cables are difficult to locate when buried. To address this problem, fiber optic cables have included a toning wire for locating the buried cable. The toning wire is typically a conductor such as a relatively small copper wire that can be used for locating the buried fiber optic cable by sending a signal along the toning wire that can be detected above ground. Specifically, the route of a buried fiber optic cable having a toning wire is found by attaching a tone generator device to an exposed portion of the toning wire so as to generate an electrical toning signal along the toning wire. A detector is then used by the craft to find the buried portions of the toning wire by detecting the toning signal, thereby allowing marking of the cable location.
By way of example, U.S. Patent App. Pub No. 2005/0053342, the disclosure of which is incorporated herein by reference, discloses a preconnectorized fiber optic cable as shown in FIG. 1 having a toning wire disposed in a toning lobe that is connected by a web to a main cable body. The preconnectorized cable includes a plug connector that allows the craft to quickly and reliably optically connect the cable. Before the plug connector can be attached to the end of the cable a relatively short length of the toning lobe must be separated from a portion of the main cable body. It is desirable for the craft to have fiber optic cable designs where the toning lobe is easily separated from the main cable body without damage or leaving irregular surfaces, while still being robust enough to handle bending and/or coiling without unintended separation of the toning lobe.
However, manufacturing fiber optic cables with toning lobes that are easily and reliably separable while still being robust presents certain manufacturing challenges. One challenge for manufacturing at high line speeds is dimension control and shrinkage of the toning lobe because of its relatively small size relative to the main cable body. Another manufacturing challenge is the wearing of the extrusion tip that guides the conductive wire into the extrusion tooling. Simply stated, as the extrusion tip wears the location of the conductive wire within the toning lobe can change, thereby altering the separation performance of the toning lobe. In other words, as the extrusion tip wears (e.g., the guide bore through the tip enlarges) the conductive wire centered within the toning lobe tends to migrate to off-center locations such as toward the main cable body, thereby causing relatively thin walls or portions about the conductive wire 12 that adversely affect separation performance. The conventional wisdom is to replace the worn tooling with new tooling; however, this involves the costs of manufacturing down time and the new tooling. Of course, tooling such as an extrusion tip may be made of harder materials as known to slow the wear, but the harder materials are generally more expensive and difficult to manufacture. Moreover, eventually even the tooling formed from the harder material can wear and allow the conductive wire of the toning lobe to migrate. The present invention addresses the problems associated with the wear of the extrusion tooling that allows the conductive wire of conventional toning lobes to migrate, thereby causing separation performance issues for the conventional toning lobes.